This application relates to scanning-beam systems for producing optical patterns in various applications.
Scanning beam systems can be used to project one or more scanned beams on a surface to produce optical patterns. Many laser printing systems use a scanning laser beam to print on a printing surface of a printing medium (e.g., paper). Some display systems use 2-dimensionally scanned light to produce images on a screen.
As an example, many display systems such as laser display systems use a polygon scanner with multiple reflective facets to provide horizontal scanning and a vertical scanning mirror such as a galvo-driven mirror to provide vertical scanning. In operation, one facet of the polygon scanner scans one horizontal line as the polygon scanner spins to change the orientation and position of the facet and the next facet scans the next horizontal line. The horizontal scanning and the vertical scanning are synchronized to each other to project images on the screen.
Some scanning-beam systems such as scanning-beam display systems use a pre-objective optical design where a scan lens is placed in the optical path downstream from the polygon scanner and the vertical scanner to focus a scanning beam onto a target surface, e.g., a screen. Because the scan lens is positioned downstream from the polygon scanner and the vertical scanner, the beam entering the scan lens is scanned along the vertical and horizontal directions. Therefore, the scan lens is designed to focus the 2-dimensionally scanned beam onto the target surface.